FIG. 1 is a sectional view showing a conventional sound transducer.
As shown, a typical sound transducer (speaker) includes a frame 1, a yoke 2 inserted and mounted inside the frame 1, an inner ring magnet 3 and an outer ring magnet 4 for transmitting a magnetic flux to the yoke 2 or receiving the magnetic flux from the yoke 2, an inner ring top plate 5 and an outer ring top plate 6 for receiving the magnetic flux from the inner ring magnet 3 or the outer ring magnet 4 and transmitting the magnetic flux to a voice coil 7 at a right angle, the voice coil 7 partially inserted into an air gap between the inner ring magnet 3 and inner ring top plate 5 and the outer ring magnet 4 and outer ring top plate 6, a diaphragm 8, into which the voice coil 7 is attached, for generating vibration by the vertical movement of the voice coil 7, and a protector 10 having a sound-emitting hole 11 and protecting the diaphragm 8.
As illustrated in FIG. 1, a lead-out line 12 of the voice coil 7 is fixedly adhered to the bottom face of the diaphragm 8 by a line exchange bond, taken out through the lateral face of the frame 1 or a groove (not shown) formed in the frame 1, and soldered to a terminal 14 along the outer lateral face of the frame 1, respectively. The terminal 14 is used to connect a pair of leads and ears (not shown) and lead-out lines (input and output lines) to one another from the outside.
A process of bonding the lead-out line 12 of the voice coil 7 and the diaphragm 8 is performed as a line exchange bonding process of fixedly bonding the lead-out line 12 to the bottom face of the diaphragm 8 by a line exchange bond. Although high precision is needed, this bonding process is manually carried out, which results in long processing time and high costs. In addition, frequent defects make this process the weakest one among the processes of manufacturing a microspeaker.
Moreover, since the lead-out line 12 is fixed to the diaphragm 8 by the line exchange bond, when electrical signals are converted into acoustic signals through vibration, mass and stiffness distribution of the diaphragm 8 is not uniform, which causes split vibration and degrades acoustic characteristics.